Telltale's The Walking Dead is a very "immersive" game that is devoted to character interaction and development. The environment for the game fits perfectly with the situations the characters are put presented with.
Dishonored: The game is detailed in every aspect. The characters are worthy of their parts. And who doesn't enjoy a good revenge motive.
Mass Effect: Great series of games. Very enjoyable and choice driven (until the end :P). However if you are a fan of sci-fi books you'll probably find M.E a rip off.
While I'm sure The Last Of Us is a good game, if someone's asking for game suggestions on the PC message boards, I'm not really sure how suggesting a PS3 exclusive is going to help...
I actually have a lot of interest in The Last of Us and have not yet played it. At the end of a console generation most gamers have access to home consoles in addition to their PCs.
All of these are good suggestions!
To be honest, I'm getting very tempted myself to buy a PS3 just to play The Last Of Us. It's nearing the end of it's lifespan, and only £150 for the super slim 12GB model, so I might pick one up soon for The Last Of Us, and a couple of other exclusives, like Dragons Dogma and Heavy Rain.